The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1887-01-18
MAKING LEAD PENCILS.
DAILY CONSUMPTION BY THE COUN-
TRY ONE-QUARTER MILLION.

Separating the Graphite Dust According
to Fineness-Mixing the Clay and Fore
ing the CoiI-The Wooden Case and
Filling 1t.
The consumption of lead pencils in this
country is estimated at $4,000 a day. This
is at the rate of one per day to every 100 Of
population or about 900 a year.
Graphite which is the softest substance dug
from the earth, is taken in the lump direct
from the mouth of the mine to the reducing
mill. Here it is pulverized by stamps under
water, the particles floating off with the
water through a series of tanks 1t comes to
the factory in Brooklyn in barrels, in the
form of dust The powder is lusterless and
of a dingy color. 1t is finer and softer than
any -four, and can be taken up in the hand
just as water can, but is hardly retained
more easily than water is. If one attempts
to take pinch of it between the forefinger
and thumb it is as evasive as quicksilver,
and the only sensation left is that the flesh is
smoother than before
The first process in manufacturing Is to sep
arate the graphite dust further, according to
fineness. 1t is mixed with sufficient water to
run very freely, and is then turned into
hopper, from which the water runs slowly
through a series of tubs The coarseSt and
heaviest particles settle to the bottom of the
first tub, the next cOaTsest and heaviest III the
next, and so on, the movement of the water
being made very gentle. On reaching the
last tub, the powder, being twice as heavy as
water and sinking in it if undisturbed, has so
far settled that the water discharged at the
top is nearly clear After the flow is stopped
and the powder allowed to settle, the clear
water Is withdrawn by removing success vely,
beginning with the upper one, number of
plugs inserted in holes in the side of each tub,
care being used not to agitate the contents so
rs to disturb the deposited dust. This being
done p ~erly, the deposit is removed through
the gates at the bottom of each tub. The
separat n is thus performed, by this ingen-
iOus pro leSs of Floating, more perfectly than
it could by any direct handling, dry treat
meut being wholly impracticable. For the
finest pencils the deposit from the last tub
only is used, but for ordinary and cheap
grades that from the two before the last will
answer.
READY FOR THE CLAY.
The graphite is now ready for the clay
This is peculiar pipe clay, from Germany
After being subjected to the floating process
the finest is mixed with the graphite, in pro-
portions varying according to the degree of
hardness required. The more clay used the
harder the pencil. For medium grades the
proportion is about seven parts clay to ten
graphite, by weight. The graphite and clay
are mixed together with water, to the con-
sistency of thick cream, and the mixture is
fed to the grinding mills, which consist of two
fiat stones, about two feet in diameter, placed
horizontally, only the upper one running.
Between these the mass Is ground like paint,
for the finest pencils as many as twenty-fOur
times, thus securing the most perfect strength,
uniformity and freeness from grit i'll the leads
After grinding the mass is inclosed in stout
canvas bags, and the clear water forced out
by hydraulic pressure until it becomes a thick
dough.
1t then goes to the forming press This is
simply small vertical iron cylinder, having
a solid plunger or piston driven by a screw.
A plate is inserted in the bottom having an
opening of the shape and size of the lead de
sired, and the graphite is slowly forced
through the hole, exactly as water is forced
from a syringe, coiling itself round and round
like coil of wire on board set beneath the
press. The coil is taken up at intervals, ''rove"
off straight by the hands into lengths sufi-
cient for three leads, which are Strengthened
out, laid in order on a board and pressed fat
by putting a cover over them. They are
finally hardened by placing them in a crucible
and baking in a kiln. The handling must be
done expeditiOusly, as the leads begin drying
Immediately, and become brittle as they dry;
but on first issuing from the press they are so
plastic that knots may be tied loosely in them
THE WOODEN CASE.
The leads are now ready for their wooden
case. For the cheapest pencil pine is used y
for the common grades an ordinary quality
of red cedar. At the saw mills the cedar is
cut into blocks, about seven inches long and
these are sawed into strips about three and q
half inches wide and three-sixteenths of an
i.I-
glued together, with the lead between Each |
strip is wide enough to make the halves of
six pencils The pencils are made six at a |
time, and imperfect strips are put together SC |
as to make a full strip out of the parts
When these boards (which are now ready for |
shaping) reach the factory, they are first |
passed into a continuous line, under cutter |
which cuts six little grooves, round or square, |
for the leads, and snooths the faces by the |
same stroke. The lead in the foreign pencil |
lies wholly in One-haf of the wood, the other
slip being put on as a cover, as nearly every
body has found occasion to know by the
covers coming off and leaving an unpleas-
antly fiat surface; but the American method
has the groove equally in each strip Accord
mgly the two strips are glued alike.
Filling the leads IS done by girls, sitting at
brass-covered tables. The first takes groov-
ed slip with her left hand and bunch of
eaos In her rlghU. spreading these out In her
fingers like the sticks of fan, she dexterous-
y lays them in the grooves and passes the
filed slip to the girl at the left, who puts over
It another slip which has just received a coat
nG OF hot glue from a brush welded by
bird Any two slips fit together, and the
United pairs are laid in a row and pressed to-
sether in an iron frame by a screw, and the
'ow of slips is left to dry. The rough ends of
he slips and the projecting parts are next
ground smooth against a wheel covered with
andpaper, and are then ready for the process
# separating and shaping, which is done by
V. H" III Brooklyn Eagle.
Cosmopolitan Character of Bombay
The cosmopolitan character of Bombay is
Indicated by a missionary letter: "Last week
! Greenlander called, seeking work Two
lays after man from Australia wrote me